1. Field of the Invention
The invention relates to optical fiber connectors generally, and more specifically to means for "fixing" the relative rotational position of the eccentric sleeves of an eccentric ferrule optical fiber connector.
2. Description of the Prior Art
Optical fiber connectors having one or more eccentric ferrules, one over the other, with the outer one rotatably mounted within an eccentric axial bore through the body of the connector are known per se. U.S. Pat. No. 3,936,143 describes such a connector arrangement with pin means for rotationally "fixing" each ferrule with respect to the others once an adjustment has been effected. The eccentric ferrules or sleeves are called collars in that reference. Since the relative positions of the eccentric sleeves are not known until the adjustment has been empirically accomplished, a bore for accepting the pin can obviously not be provided in advance except in the outer sleeve or collar. Beyond that, drilling in place to extend the pin accepting bore into at least the next innermost of the sleeves would appear to be necessary. That procedure is of itself relatively inconvenient and cumbersome.
U.S. Pat. No. 3,800,388 suggests clamping or locking such eccentric sleeves in place by temperature shrinking, the use of guide pins, soldering, welding, clamping or gluing. The connector bodies for the optical fibers aforementioned are very often fabricated from stable plastic materials and are accurately manufactured. Accordingly, soldering and welding are not available alternatives, nor is the "shrink fitting" method applicable. Clamping might be employed, however, clamping devices are frequently more cumbersome and larger than the apparatus they are intended to clamp, and gluing or cementing implies a drying or setting time, however, relatively small that may be.
It should be borne in mind that the typical optical fiber to be connected in a fiber optic connector arrangement is a hairlike element a few thousandths in diameter including core and cladding. Accordingly, the "fixing" or locking problem remains only marginally solved in the prior art.
An approach to the general problem of optical fiber coupling based on a somewhat different principal is illustrated in U.S. Pat. No. 4,019,806. That reference could not be considered to be a dismountable connector arrangement, however, and is otherwise not germane.
German Pat. No. 2,358,785 employs the eccentric sleeve principal with a somewhat different apparatus for locking the movable components in place, that apparatus would not, however, appear to be convenient or easily applied in the field.
In view of the state-of-the-art for locking or fixing eccentric sleeve members in the type of optical connectors aforementioned, there would appear to be a substantial need for a simple, inexpensive means for accomplishing such locking or fixing. Such a means should be simple, inexpensive and quickly and easily applied in the field with simple tools, since optical fiber systems are beginning to be used and are expected to be much more extensively used in the future.
The manner in which the present invention addresses the disadvantages of the prior art to provide a novel structure and approach to the problem will be evident as this description proceeds.